To the sperey gybqscope



sept. 1s, 192,3. 1,468,330

E. A. SPERRY SYNCHRONOUS TRANSMI SS ION SYSTEM Filed Dec. 5, 1919 3Sheets-Sheet 1 hun 8 7562 "iw 151.5-, 71" 73 4a 5a ,1f 4,` -5

'5B 42 J4 INVENTOR f2/VER /EPf/my.

IMs' ATTORNE Sept. 1s, 1923.

1,468,330 E.A.sPERRY lSYNCHRONOUS `TRANSMSSION SYSTEM :s sheds-sheet 2Filed Dec. 5, 1919 :15mm nimm@ INVENTOR H/ ATTORNEY.

` Sept. 18, 1923. 1,468,330

E. A. SPERRY SYNGHRONOUS TRANSMISS ION S,YS TEM Filed Dec. 5, 1919 3Sheets-Sheet 3 INVENTOR 5mm f7. 5pm/2 y.

'Hfs Arron Ev.

Patented Sept. 18, 1923.

UNITED sTATEs 1,468,330 PATENT yorifice.

ELMER sensei, oF BROOKLYN,SNEWYoni-Assleilron 'refrn sPEInY GYnoscoPn'CoMPAN'rg or BRooKLYn, NEW lYomgii conronsnoir or YNEW Yonx.

SYNCHRONUS LRANSMLISS'IQI SYSTEM. i

Appiication mea December 5, mier-serial Noswess.

To all/whom 15mm/concern? A Y i Be it known'that I, Emi-m12 A. SPERRY5.g1, citizen yot the: United States ot America, residing zit-1505Albermurle Road, Brooklyn, in the county of Kings'and State of New York,haveiinvented certain'- newand useful Improvements linSynchronous-.Transmission Systems, of which the following is aspecification' n t This invention relatesV tov transmission systemsadapted to position an :indic'tor or other element in accordance withthe position of u remotelyr located element, and has for one of itsobjects-to royide meansfor indicatingi with a high agree offfaccu'racythe position of such remotely located element. v "i Another object is toprovide-nn indicator which may be automatically" restored-Vtosynohronism Whenit herstellen 'out-of step with its transmitter. This"is'psrticuleily advantageous in vfire control systems, 'since it thecurrent should go off at a. critical time while the trimsrnitterisbeing`moved with relation to the indicator.; synchronism between saidtrnnsmitter'and indicator will be automatically "restored When= the"ycurrent comes on. ivi-4 z 'i Other objects are to eliminate all makeVand breek contcts such as are 'commonly employed in transmissionsystems, und ait the same time to provide a, stnrdy,"rugged and smoothrunning system of transmission.

Referring now to the drawings whiclrillustratc whatI nowf'consider the;preferred form of my invention: L f Fig. l is an elevation of thereceiving-'apperatus, parts being,r shown in section.` Fig.4 2 is a sideelevation of a spinning-'up mechanism Jfor :i motor, certaincircuit'eonnections beingr indicated ding'rammatically. Fig. 2 is splalnview of the'partsshown innige Fig. 3 is :in elevation of a, sendinginstrument the cnsinf"y being shown insertion. i

Fig. 4 is a detail of parts shown in Fig. 2. Figs. 5. 6. and 7 uredetail views of parts Shown inFig. l. i u v Fig. S is :i side elevationof certain clockwork mechanism, the casing being shown in section.

Figs. 9. l0, ll, and 1Q are detail views showing' different positions ofparts of said Dlovltvrrirlt mechanism.

,Fglis :L .wiring diagram. Fig. 14 is ai detail .View of` certain.indicatigpmeens shown in 1.

Fig-15isgadetailplanview of an arrangement of eertaincontacts shown in;Fig.

1...*:1 6 :fsw

.; Fig. -ltis lear-plan-viewkof parts shown in My;clevice isttiapable ofwide lpplicationa.

and maybe used for-indicating the angular position of any remotelylocated object, such as a sightinginstrument or the readings .ofacompass'icard.; :In-Eig.` 3 -I have shown by Way/of 4exampleia sendinginstrument comprislng a.' casing l provided with asha'ft Qjournalled insaidcasingand in a bracket .Ai pointer-4 mayfbe .mounted Aon said.-shaftiforf cooperation with a scale 5 on said casingf- Obviouslysaidshait 2gmight also@ e'e-rryi any` other object,.rsuch as a. sightinginstrmnenti; the enguler` position of t which .isi` to Abe transmitted=to' a remote point. Fixedfto 'said-shaft is a, gear 6,-1Which mayvmeshfvi'ith aeromrgeer 7 connected with a?? handlelgwhereby shaftf maybeirotated by hand. Such rotating means it willl be undesstoodiisfinerely shown as illustrative .-'of",any ynotatng meen@ power-`driven or Yidedimieesns;hier -woperetion Aivi/ith pointer :4i Onih-Sh-ftfofiitiansmitter 10.

Transmitters: 9 end .10 fare wnneoted yt0 thesending?instrumentfthefiformer being eonnectedis'irectly to shaft 42;and the latter -to employ-instruments of'fa typewell known lin.theart,== ainctn each:con'iprisingEaV three phase stator and a. singlephase rotor.

Suitable means-may be-connected with repeater'motorsl and .'13 Vfor.indicating accurately the'` position of. pointer 4'. One form of suchmeans isshown in Figs. 1 and 14, wherein a reference; member, such as acircular'scale 16 is4 attached toshaft 17 of repeater -and a.corresponding circular scale 18 concentric with Scale 1.6, is connectedto 1:

" .Connected to -saitl a sleeve 19 driven from Shaft 2() of repeater 13byf any `suite le-mean s. siichas-gesring 21, 22. Mehlis" 5 chsadoblpbinter fixed with relation to scales 16 and 18 as by i"183 Thiry"be graduted f `to @fe-es; mi 'Seule 1e iQ-indicate Mimet-dend minutesgas showninF'g-ljLU-fjn oouratefres'dingoffjthe 'position- :pointer maythereby be geurdrif "l" T' 1in'` transmission systems of thentype-de-*scribed* the` repeater Arfotor vY-*follows by Steps the -position'ofthe'trensmi literj rotor, ad the number Vof steps dnringo'ne comlpleteTotaaccordance i with various faetor's; Gueb 32sthe strength of current,Charctertofr'torrd stator windings, etc.' 'By' suitably lgearingtransmitter 10 to shaft 2 'and scaleilS" to s'hzi'ft 720,- it isevident' that jsaidscale'ltzrn. be2-moved through one-minute steps. `F0rex'anupie if the shaft "of 'transmit-ter 10 makes one revolution during`the rotation of pointer,4 throughl four eg-reesl pd the rotor ofrepehte'r'l plisseslt rough ,6- steps during one revolutioxrof saidshaft, one step throughjwhchsgd rotor turnswll be, equivale-ump 211/2.i1'1nptes, and ednsefquently if one step., of -sea1 e 1 8 `vill beequivalent to one minute of are. It is thus possible to read Jiheposition of inter 4 accurately from circle 18 to one minute of arc.

With the gearing above described, it is yapl parent that' scale .18maltes' revolutions to one'-l'evolbion-#off-pointer?t :ind hence 'ofseele 16. slhnvnt inl :Fig: 14; -the matin ,-gradationso scale d6',orresponding to the numerals `thereon',-design'ate tens ol"clegi'ees,Vthere"beingf 36 Isucl'fgrsidnations, while smi le -1S,x1'ray'b'edivided' ito ben mitin parte, represented by the heavy faced numerals.,:designating unitsof Hevre'. and enchs'iich-mnirilprtnmayfbbfiyidedlinto imy suitable numbeh ofpartsfor,indieztingaminutes By wyso .exa.lnile,l:1f'hztve shown such main-lprtsnasa lalming; :Eour-min slib-divisions 90 ,eachsubdi 'sonunitube-ih'gdivided into Y -sx smaller fsubdi=visions; 0f conrse, .the numberof sub-divisions can be variadas denlsorifzdesiretl,;be}suitably4enh-divided, :is 05 ffm? mstancmld ten {eq'ufrhsub-:divisions Aforzflilsflidicatin'g units oldegrees. f- A f' wnln,ordemoizvdegreesgnndminutes to be :.rexlhaecirrn'tely imm uales 16am-,18 'it is:essenftal'thats,@Minnerelationship between )on .the glflnabions'onithesca'les be arm i nt'aine fl '-f `.FoiYexsmnplinthesi:erfbntdieajton i'on scale 1S imustf Ybe opposite the.lreferente mark -on pointer 23 Whenever one of the numero-lsV in--Jdicatig bnsolegrees on-1scsle16fhes0pmr positensniclfmeferecea murlmf-Furthermore '21, :1f 'said rseiforencermlrk;iesfopposi'te .1 pointmatihsvon sale18'are in. the proper rela- 'tibnstprtoithos'fo'seal sothsit the inf-li- :catdns-Yf are g prbprlyfsynohronized when thecircuits through the transmitters and repeat-cigare'closetLI-'huveprovided the fol- 12|* lowif' medianisrv 1 'Y .A p iimlityof fcontct's29, 30, 31, 3Q may be'muntedon''eslmft 33 driven ns through Gears 34,35, 36, and 37 from repeater shaft esch-nr'iayroonsist4 of a-doubfleContact porif tion 38 and insulation portions 3S) and 40. nBrushes 41may be provided for enghgeiment-With the peripheries 'of -Suid contactsThe Contact portions of contacts 29, 30, and

,- cooperating brushes which contact -with: :ontacts29, 30,

` from under .itscorrespo'ndinrbrush.

31 are. so arranged that when a contact portlonof one contact'passes outfrom under its cooperatlngfbrush, a Contact portion of .the next-contactwill me under its corretachment fof lead-,Wires 43, 445and 45- f;The

gearing between 'repeater shaft 17 and'shaft 33= ispreferably. suchthatwhenthe scale 16 has -mo'ved fromv one rtendegree indication to-thenext, acontact portion ofeaehcontact 29, 3m-and' 31 has assed from underits brush-. 1 ading-z :fromV the .whichvare connected to :oorresp'ontlincontact segments 146,. 47, -andi481mount Aon a bracket V49beneath'aseale' `18. v1Bracket ,119 ,may-befsupported infamy suitableway, as -by a. braoket'-l mounted -inf the casing V25.

As s'hownrin 1 'andlrcontactsegmentsr46, 47,-: andi'48 are insulatedrfrom each-other and Ileach' majffextend along an Harfe o: substantially=1205l Movable-v' with "scaley'18, Vasl by being attachedvrthereto, is aportion; -52 ofwhich ductor 56 connected Withftheotorofre- 'peaterlthrough'one' of brushes27: f Segments 46,47,"and 48 fare'eachfprovidedwith Y mi afbinding-post57fo'rthe attachmentlofrconductors 143', 44;tand 45; respectively i i ment with -the borres'ponding contacts. 'fiFbrlowering the vbru'she "into 'engagement with their 'cooperatlng contactsI' have shown '1 mechanism ina casing'94, the operation of Which'will"lne-described in detail later.

with imparts 'ums'f far' described cnfnectedrelectrieally'"as shownin'Fig.` 13,

f Switcliz being-@penned saircii'erciosed, it' `"vill The? seen' what*no rrentf mmf-aow llone'of"contact"'segments 46,'T, or48 corre-Spomiing ,wier that jobf contacts 29, 30, foi-,31 whose contact portionis in engagement iwith itscorresponding bifushAl. Y Upon theestablishment of such current flow, lthe rotor of repeater` 'willbe'strung. intoy a position 'corresponding' with the: position of the rotorof transmitter'` 1 0, as is well under` 'stoo`d,and the'scal'e 18 movedaccordingly.

Ifcurrent could flow through both trans mitter 10 and repeaterl 13immediately upon segment 46,.assi1ming-brushes 41 to have been'loweredK-However, when .-thef zero y:point on scale 16 has imovedthroughAP, conthe closing of switch 6i, while the rotors of saidtransmittenand repeater wonldassume corresponding angular positions, therelati'on. between the graduations of scales 16 and 18 might bedisturbed. As an example;- assume that the zero points on scales 16 andv18 correspond with the reference mark on pointer 23 and that the switch129 is open with rotors 111v .occupying the saine angular posit-ion. Ifnow pointer .4- be turnedh through 4- the rotor of repeater12,and hencescale 16, .will'be turned through 4 also.- If at: thistime switch 129were dlosed, scale 18 would not be moved, since=`the-rotor oftransmitter 10 has turned through 360%.80 back to its original position,andhence again -occupies the same angular position as the rotor ofrepeaterr13..- The scale 18 -would -hence indicatera reading ofzero-.degrees Bythe arrangement which1 -I have providedr however.whenever scale 16 turns through A1/3Sof the angular distance betweentwofad- Vjacent ten degree indications, a'contact portion of oneoffcontacts- 29,- 3Q, and-31 sli-ps out from under itsV cooperatingbrush-andai a contact portion of `theznext contactfeomes into positionfor. engagement -byfitsi-brush, and if such brush'es.- are lowered :bycams 58, and brush 152 is engaged-'with fthe segment T46, 47, or.48.electricallyconnected -with lthev last mentioned v.contact portion acurrent will flow "through rotorsll-f In the example above givenwhenthezero point ofvscale 18 .corresponds'lfwith the, reference a mark onpointer 23,.=brush 52 is in-contact with seg-f100 ment1465-.and-When thezero point -of scale 16 corresponds with said-:reference mark, contact.portion 38' of Contact 29 is in engagement with .the .brushelectrically connected4 with 5 tact portion-38 of =contact 29r haspassedf'out lof. engagementv with its brush and contact portion38o`f-the-fnext rcontact 30-has come-410 into engagement withthe brush,electrically 4vconnected with segment; 47.- Inty order'for-ffcurrenttolow through rotors 14 Vitis'thus "essential to bring. brush52 into contactwith segment'ift', which necessitates movement-115 ofthe-zieropointof scale 18 through 1/3 of ai revolution orA until; thereading on scale`18 opposite the reference mark onv pointer 23'is3-1/30. Suchmovement ofscalelS fhasresuil't-` ed 'from :i turning oftherotor ot'arepeater-l-B,` by meansilater to be described, and correspondsto a turning of said rotor through 5/6 of Va revolution. When saidrotorhas turned through 5,/6 of a revolution, however, brush 52 havingbeen brought thereby intocontact with segment 47. current will fiowthrough rotors -14 and the rotor of repeater lil will move. :is is Wellunrlerstoodiin' the art, into' the same angular position as the rotor oftransmitter' 10. The rotor of reoul peater 13 will, therefore, in theexample given, be moved through the remaining 1/6 o`f 'a revolutionnecessary to bring it into the same angulaiposition as the rotor 'oftransmitter 10, an'd this wili result in fa further turning of scale 18through one-Fifteenth of a revolution or through two-thirds'of the distance between two adjacent numerals indicating units of degrees. Scale18 hav-ing already been moved to a position wherein it indicates 3-1/3"will hence b'e movedithroug'h two-thirds the dist-ance between the 8 and4 degree indications, which will bring the 4 degree `indication intocoincidence with the re erencc m'ar'k on pointer 23. Th'e'scale 18 willthus Vindicate correctly the number of degrees through which pointer 4hasturned. The scales 16 'and 18 are tiren in their correct relationshipand switch 1-29 may be Iclosed. From the arrangement of segments 46, 47,'and 48 and contacts29, 30, and 31 with relation to the gradu'ationsori-'scales 16 Vand 18 it Wll b'e seen that Ia circuit cannot be closedthrough rotors i4 when switch 129 yis open until -a point is reachedsuch that 'by the passage 'of 'current through said rotors the readingon saaie 18 c'anbe causedt'o seppieiment exactly those offscale r6.

'One form 'of 'means for causing a rturning off the rotor 'of repeater13 for moving brush 52 is lshown in Figs. 1, 2, :1111014 and is con-'structed as follows: Mountejdfon'shaft 20 of repeater 13 is a 'gearwheel 62 adapted to mesh with toothed se] ent (i3-ruminanti on la'n'aim64 p'i'li'oted to a Molet'i on the casing 'of repeater 13. A 'spring 66,-con- 'netted at one 'e'nd with arm 64 and at the 'other with post 67normally 'urges arm 64 toward the right asshown in Fig'. 2, but said'amm yis normally prevented-rotti suoh movement fby means 'of a 'sidableShop@ passing through bearings 69 and ,f on the casing of repeater 1'3and engaging at -rts upper end with fa suitable projection on arm 64. -Ihave show-n :such prdyecti-'on as the.

'end 'of a rod 72 pivoted to the anni 64 -for a purpose to be Yexplainedlater. The lower end 'of rod 68 bears, preferably through a roller 7-3,on the periphery of a Aearn 74 mounted on 'shat 7 5, whidh shaft *mayalso carry the cams 58 he'reinhefore described. A Ispring 76 connectedat 'one end to a projection 'on rod :68 and at `eits other Vend to`-bearing 76 may be employed to aid in keep fing roller 7 3 at all timesin engagement with the periphery off cam 74. When the cuttaway portion77 of cam 74 reaches roller 78, 'during rotation of the nam, the upper'end of stop rod 68 Will obviously be withdrawn from engagement with"the end of rod 72, whereupon spring 66 will pull Yarm 64 to the nig-ht,'as shown in Fig. 2, v-afnd thereby cause lthe teeth on segment 63 toyrotate gear 62 and hence shaft 20. The rotation iin-parted to Igear 62and shaft 2() by segment 63 should be suicient to bring brush 52 intocontact with that one of segments 46, 47 and 48 which corresponds withthat one of contacts 29, 30 and 31, whose contact portion is inengagement with its corresponding brush 41. ln the construction Which` Ihave shown, the rotative impulse imparted 'by segment 63 and spring 66to shaft 20 should be sufficient to cause rotation of said shaft.through more than one revolution, such rotation con- -tihuing until acircuit is closed by brush l152 through repeater 13. For returning arm64 to its position, shown in Fig. 2, I hare shown -rod 72 as connectedwith the armature of a solenoid 78, connected as shown di'agrammaticallyin Fig. 2 with a battery 79, one terminal=of which is connected to aooitact mounted on and insulated from support 81 fo'r the repeater 13,and the other terminal 'of which -is connected through insulated brush82 bearing on a ring 83 ot' 'cam .74. Ring 83 is suitably insulated fromshaft l75 and is connected to a contact segmont 84 on lcafm 74. Theparts are so delsigned that, after arm 64 has been pulled by spring 66to rotate shaft 20 and before stop rod 68 is moved upwards to itsposition shown in Fig. 2, ContactI segment 84 will be brought Aintoengagement with Contact 8O iaidsolerid 78 awill thereupon be 'energizedto move arm 64 back to its position shown in Fig. -2 and to hold saidarm in such position until after the upper end of stop rod 68 is movedin .front of the end of rod 72, asv` shown -in Fig. 2.

Sincegshaft 2() must not -be rotated when anni 64 vis returned bysolenoid 78 to its original osition, means should be provided for enabing-gear 62 tovturn idly on said -shait when a-rfn 64 is being returned'to its originally osi'ton.` @ne form of lsuch means I have disclosed inFigs. 2 and 4 wherein gear 62is shown mounted to 'turn 4 loosely onshaft 20, and has a hub 85 lprovided with ratchet teeth `8 6 adapted tomesh with corresponding teeth on collar 87 attached to shaft `2,0 torotate tlierewith. A spr-ing 88, show-n in Fig. 4, serves to yieldinglyAsupport said gear wheel. From the construction shown, it will readilybe seen that when toothed segment 63 moves toward the right, `shaft 20will be rotated through the inter- -meshin of the ratchet teeth on hub85 and ollar 8 ,but that, when said segment moves hack toward the left,said ratchet teeth will slip over each other and gear wheel 62 will turnWithout imparting any rotation to shaft 20. Obviously any suitable typeof ratchet. -connection may be used between gear 62 and shaft 20, Theteeth of segment 63 should preferably be out of Contact with gear 62when arm 64 is in the position shown in Fi 2, thereby enabling gear 62to turn Wit shaft 2() when said shaft is rotated.

ill

In Figs. land 7: 1 haveishown one forrrrofv means for operatin switch'blade 129. A cam 90 on shat' is designed with a pros.l jecting portion91 adapted, when said cam is turned, to move switch bladeA 129into thedotted fline position in Fig..7 wherein it may.

engageV between cooperating contacts '92;`V Only one of-said contacts isshown'inFig. 7:- Theblade129 is normally-biased to; its open` or ful]line 'position by a spring 93. -1

vFor operating stoprod 68, brushes 41 and switch 29 I prefer to employmeans-operated automatically :by the making andbreaking of the maincircuit 28. lOne orm of such means is shown in Fig. 1 andin detailin iFigs. 8-12 and is constructedsubstantially asfollows:

Containedv within a casing 94 is a clock'- work mechanism comprisingasetrof Agears' 95,96, v97.411111 .98, driven by a spring-60,

" shown in dotted lines in Fig. .8',said springl being attached at oneend to casing- 94;. and at the other to gear 95. Said gear 95' iszxedlyattached to' shaft 7 5 torotate 'theflatterl' Mounted to turn with gear98 isa: pair of arms 99,1 each provided with a-.projectionJu-'henv-mgnet. 107-`is deenergized. .w1 .Betweeni pivot 101y andarmst103` and 104r arm-102 is? providedivvith4 aideperidingwpor-f;

tion carrying a roller 110.1' Y@nrgear wheel- 95Jare projecting surfaceslllfand 112`,lwith. whichrollery 110 sadapted to cooperateimaman'nerznowto be described; f 1: if .F 'w- In Figa Y8 the-v partsijust'described are inthe position normally occupied when'no cur' rent ispresent in mains-28. In vthis posi tion, projcction-105lies -in the path'of a projection 1002 Ifxnow a circuit l'is closed' 5 through mains 28so that current flows there= through, armature 106. is drawn Vtowardsmagnet 107 and projection 105 raised out of: the` pathof'projection..100iv Before, however, armature-106 has moved towards magnet101e-sufficient nmountto bring projection 105 into-the pathofprojection-100,1. roller.110 is brought-into engagement witnprojecting surfaces111v` andv further downward movement of armature 106 is` prevented. Theparts then occupy the position shown'in Fig; 9.; The gear train `95l`96, 9'?,` and 98-is thus free to-be rotated by its spring. Such rotationwill yoccur immediately: and will continue until gear 95 has turnedthrough lofwhereuponsan offset portion 1213' of surfacelll -is broughtopposite roller 110i and'armature'lOG' then movesl further downwardlytowards-magnet 107 until-roller 110 contacts with the 'said .offsetportion-113.

At this time, projection 4105- has been brought opposte'one ofprojections 10() (see Fig. .10)VA and rotationfof thegear'train incasing 94 ceases. Theparts'remain inthis Y'. position 'until the'circuit throughl mains' 28 isbroken.` Thereuponyspri-ug 108 acts toraise armature 17061and1 therebylower arms- 103 anrl.:104.l Before',however,' projection 105- is .iloiveredfinto the path of -proj'ectionf100, roller ll'come's into contact'x with sur! face 112asshown `in Fig.11 and gear 95 is again free to rotate; Projecting surface- 112 ismounted eccentrically on:E gear 95 and'isi so designed that," when saidgearhas turned through one complete revolution,y roller 110 has beenpermittedto movedownwardly far enoughV -for projection .105 to be 4oncemore'brought tinto'the path: of a' projection 100 (se'eli'g.581),.1Rotationofthegear train is again stopped/and 'willfnot take place againuntil armature 106 isiagain attracted bymagnet 1071.v ifv -i.- j 1During one complete rotation of gear 95,

shaft? 5 of course'causes 'cams1 74, y91., and- 58 each to .nia-k: onecomplete reyoiution. f These cams are so constructediand' arranged withingsythati they 'operate .in-.tihe following se uence: .ri 5 it i yencurrentstartsfto- How `in mains 28 and gear 95 commences torotate,'a"certain amount of rotatonof V`sairlwgearjy sayrl through90,1without icusin" the `spinning up Vof shaft 20 'zis pennittetdfisd'that .if pointer 4 is. being moved lscale-16 canfbeibroughtintosynchronism-with Vsaid' 'binter.--As ear 95 continuesto'rottelsayiveyond: 90' t e'fidttened vportionw? of Acan1g74is broughtbeneath Vstop "rod 68, and the: repeater? shaft" 20is therebyspun .uptoset 'arm 51 ii'n:1no

tion.: I-tshoul'd benoted -inthis connection that spring-66 shouldf'nothave sufficientv strength to turnfshaft 20 against'the action of thecurrent :whichl flows when' a circuit is closedv through repeater. motor'13. `4After such circuit has-beenclosed theposition of shaft 20 isgoverned fbythe currentlflowing andnot by spring 66..` The vpurpose ofsaid spring is Vto':rotate lshaft 20, and thereby brushes`52,fandn53,until a current Hows through repeater motor 18.: VVh'en gear 95h asturned-through 135Q'cams 58 lower brushes 41 into engagement with theircorresponding contacts so that current can flow through rotors 14 whenbrush 52 is in contact with that one of segments 46, 47'and 48 which isconnected'to that brush which is in engagement Within contact portionofone of contacts 29, 30, and 81. It will he seen that cams 58 are sodesigned that brushes 41 will be maintained in contact with theirrespective contactsA until gear 95 hasA turned through about 280,whereupon the brushes willibeallowed to spring back to theirnormalzposition and will not be a load on rcpeater l2. By `the time-gear95 .has turned through about 265, suiicient time elapsedA for the.scales. v16. and 18 to. be brought into thelprojectiug portion91'of cam90 thereupon moves sWitch.-b1ade129 into engagement with contacts. 92,and thereby closes a circuit through..rotorsJftV independent of thebrushes 41 and 52, vGrear 95thencontinues to rotate. until.it-hasturncd; through about 3102, asfahoveexphined, when rotationthereof ceasesuntil the, circuit-through.

mains .28. is. broken. The parts are preferably so. designed that. gear95 :turnsthrough 310.o inabouttwoseccnds `B y the time that ear95.haslturned through :31(19 a circuit.

t 'roughlsolenoid TS'Willihayebeenimade and broken, so` thatv arm 6,4-,willrlhaveqbecn. re-v tracted, and,I beforefthe .circuit throu saidsolenoidis; broken, stop. rod .fwi again have been moved into the :pathof the. end of rod 72. When current ceases .t0..riow through mans28,gear 95 .will..rotatel'frpm its 3109 position toits 3609l position,during' which time, for exampleiwhen=the325 pc- Sticn is. reached, cam.to return switch blade .129 toits ,fulalline positionfin Fig. 7, andthecircuit through rotors 14 is broken. The parts are. then imposition torepeat the .cycieofoperatins above FIori-ih.: 'i 1 i 4 Itis. notnecessary. thatithe Ycycle of op.- erations `performed i by 75 follow.the exact sequence described, as brushes 441 might be lowered beforeinstead of after motor shafti 20 is s unup.

It will be .thus seen .that means for enabling one to read :easilyandaccurately the position. o-a distant object to minutes of arc, andfoninsuringtbsat the cooperating indicators. are 'properly` synchronizedwith eachother before coming into operation. As has alreadybeenpointedout, repeater motor 13`a.nd scale-18 are automatically broughtinto., synchronism with the transmitting instrument 'including thepointer 4 when brushes 41 and 521engage contacts electrically' connectedlimits. Beyond suoli limits, that'is, when brushes 41 and- 52donotengagecontacts electrically connected with each other, said repeatermotor and scaleare not self-synchronizingand, therefore, must be.brought within such limits before they can be selfsynchrqnized with 4thetransmitting instrument. The means for bringin said repeater motor andscale within suc limits com hastheirI correct relationship, and

90.1permitsispring, 93=

the clockwork shaft.

'have provided .with each: other, and hence said repeater motor andYscale. are self-synchronizing within such" 30, and 31 Which-are governedby repeater` motor 12. The latter motor and scale .-16 always move insynchronism with the transf mitting instrument and, as has already beenexplained,V if pointer 4 should be moved when the current is off,repeater 12 and scale 16.-automatically assumeva position correspondingto pointer 4' when the current comes. on, .scr-that repeater `motor 12and scale lrareecom letely self-synchronous.

It should, furt iermore, be noted that no make andbreak contacts ascommonlyuse'd inftiansmission systems are employed, and hence the y.inconvenience -of frequently. adjusting and cleaning such contacts iselimimated- Furthermore `a. fiorefpowerful torque can be obtained'=inf=my improved transmission system thanA can be. :obtainedf with. thefordinary'4 dfirect-currenty make. and4 break. `'contact transmissionsystem.` The humming noise incident to 'the flowl of thealternatingcurrent employed in the system whichzl have disclosed,moreover, furnishes a convenient indication that the system is inoperation. A

As above pointedout, transmitter 10 and repeater 13 mayieachlbeconnected-impar-A allel 4to2, mains 28, which-case 4svvitch- 129 would-merely prevent i the\ 110W v of current scribed, some ofthese. may bealtered and others omitted without interfering .with the more generalresults outlined, and the invention vextends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent 1. In combination, a transmittinginstrument, arepeatingrv instrument, current mains, connections between said mainsand said instruments, a circuit closer in the connections to onezof saidinstruments, and means for automatically actuating said ci rcuit closerat a predetermined time after the establishmentofa flow of currentthrough said mains.

2. In combination, a pair of non-mechanically connected repeaters, apair of disconnected indicators controlled thereby, a pair oftransmitters connected to said repeaters 4. In combination, a pair ofrepeaters, in-

dicators controlled by .saidrepeaters,rand

means including a -brusl'i controlled by onef of said .repeaters andcontacts controlled fby f the other ofsaid .repeatersffor closing .anelectric circuit throughV oneof said re.-

peaters.`

5. In combination, a repeater-motor 1n- A cluding a rotatablearmature,'fcifi'rrent mains and means eomprising anspringiimpelledmemberY for imparting. rotation to said armature vin; res'p'nse 4 to-the establishment of a flow of currentin saidfmains.

6. In combination,Y a vrepeater motor in-A cludingr a rotatablearmature, currentmains means comprisingaspring iin lledmember forimparting rotation. -to-r :sai response yto the establislimentof avowefcurrent in said-mains, and means-*fonV 1iory mally holding said membertion ofsaid spring. Y n.

7. In altransmissionsystennihausynchronizer including a rotatableimember, means fory rotating said member,A a movable-feltment adapted toprevent rotation 'of 4said member, means for moving said element forpermitting such rotation, and means comprising a cam'surface onsaidmember and a projection on said element for preventing movement ofsaid lelement intofiposition for stopping rotation ofsaid member' untilthe iatter hasvrotated 'a predetermined amount.

8..In a repeater system, a receiving instrument adapted to beactuatedfrom a sending instrument and comprising a selfsynchronous repeatermotor connected thereto, an indicator controlled bysaid motor, asecondrepeater motor mechanically disconnected from said first motorconnected' to'said sending instrument for liner i readings -andself-synchronous withincen lain limits, an indicator controlled by saidsecondrepeater motor :for supplementing the indications of the firstmentioned indicater, andmeans broughtinto action upon excitation ofthesystem and governed by said first motor -for bringing the second mo-`tor Within such limits.

9. Tn a repeater system,'a receiving instrument adapted;` to be actuatedfrom a Y ing instrument.

armature in against the lac# r sending instrument and comprising aselfsynclironous repeater V motor connected thereto, an indicatorcontrolled by said inotor a second repeater vmotor connected to saidsending instrunientffor finer readings .and self-synchronous Within`certain limits,

an indicator controlled by said second repeater motor for indicatingfractions of the indications of the rst mentioned indicator,

vandmeans-brought into action upon excitation'of thel system forfrst"bringing the second motor `Within such limits and then placing the samein circuit with the send t0; In a :transmission system, a receivinginstrument adapted -to be electrically connected with atransmittinginstrument 'and including normally inoperaive power means,means for setting said power 'means l" or op# eration "when the currentin 'the transmission system-ceases, 'and means'for releasing said powermeans for operation Wlien'tlie current comes on.

ll'lnaftransmisison system, a repeater adapted tobe electricallyconnected-with a transinitte'r,means for breaking the ronnec-V tionbetween said repeater and transmitter .vlienthe How of currentceases,"and means brought vinto action when thecurrent comes on forfirst bringing'said repeater'to a predetermined position and thenreestablisliing` the connection between saidtransmi'tter and repeater. f-f y In at.ransinissio,'n system, a repeater, a transmitterelectricallyconnected therewith, means for breaking the connection be-` tweensaid-repeater and transmitter when the flow of current ceases,' andmeans brought into action When the current comes on for reestablishingsaid connection.

13. In asynchronous transmission system,l

a plurality of repeater motors'adapted to be driven at different speeds,and means brought int-o action independently of said motors for bringingthe faster motor into a certain phase'relation with the slower motor.

14. In a synchronous transmissionsystem, the combination with a sourceof E. M. F a plurality of electric re ater motors adapted to be V'drivenat di erent speeds therefronuand means including a source of powerseparate from said source of E. M. F. for bringing the faster'niotorinto a certain phase relation with the slower motor.

15. In a Vsynchronous transmission system, the combination AWirhaplurality of transmitters and a source' of electrical supply, aplurality of electric repeater motors adapted to be vdriven at differentspeeds by said transmitters, and means for bringing the faster motorinto a certain phase relation with the slower motor, said meansincluding a source of power separate Afrom said elecl motor to select aposition inthe propeiz'phase ,arelatiomto the slower-motor .and thenbringingusaidzfastcrimotor under the .controho its transmitter.

a .plurality of electric repeater motorsadaptsacd', to, be driven `atdifferent speeds, ia selecting device driven by f theslower motor `andadapted to ,be temporarily@ vC,.onnected i with the. ,faster motor, Vandmeans. for rotating than. estes moisi, connecting; it: withy the1esselectingdeyiceand then, breaking saidcon-l Qtio ff. 1&1. i J-....I=:. e.18. JID a synchronous transmission System, a.,re ceiivinginstrumentadapted; Jtofbe jactuatedi'rbm asending instrument and includ-.,n ing :a pluralityl of; repeater motors connected to ysaid. sendinginstrument yforsirnultaneous mdvement latdiferent,speeds, angindicator,

a one-.to-one connection y. between., said :indi, i

cater andiopaotssid repeaters@ sqnflinwdiawri redaction lgarnis between.saldfsecr .ofi4 [indiwtbrand another .ofsald ,repeaters an between.said indicators that the secondjindicates fractions. of the indicationso f the 19.- fl'n, ,a transmissioiilsysteni, Y afreceiving .instrumentadapted; to be ,actu-1 i ated .from a sendimgginstrument andincludsecond repeaterV rnotoir` connectedto; said sending'instrumentfonj movementy simultaneous with said first -mentiionedrepeater but ,atx a different speed, fan; indicator iactuatedrby thefirstinentioned repeater,.an indi- Gator-,actuated -by said secondrepeater for indicating fractions of the indicationsof the4 firstmentioned, indicator, connections between-the second mentioned indicatorand l 21. In a transmission system, a synchromeans for insuring suchrelationship:

ing a repeater,motorl connected thereto, a`

1 ,4&853130, i

sition for stoppingfurther rotation of said Y member after the latterhas rotated a predetermined amount.

'22. Ina transmission system, a synchronizer including a, rotatablemember, means for rotating said member, a pivotally mountf Ved elementadapted `to prevent rotation of 17. In a synchronous transmissionsystem,

said member, means for movingr said element for. permittingwsuch;rotation, and means comprising.cooperating parts-on said elementandrmember for moving the former into position -to stoplfurther rotationof said member-after the latter has rotated a predetermined amount 23.In a synchronous transmission system, aplurality7 ofielectric repeatermotors adaptedito be driven at d-ierent speeds, meansbroiight'intovactionby the excitation of the system forimpartingmotation tothe faster motorabe'fore-theflatter is` electricallyconnected to thesystei'n, means for temporarily closingwa circuitthrough the faster motor when the `llatter has: attained-a certainrelationship-totheslower motor, and means for subsequently; establishinganother electric connection between said faster motor and the--Systenrand breaking. said temporary circuit;

24. In a synchronous transmission system, a plurality of` electricrepeater motors, transmitters connectedwt said repeaters, respectively,-a'nd=to a source' of electrical `supply for -driving's'aidrepeaters atdifferent speeds, a vcircuit 4closer-.for placing the faster repeater-in'` communication with said' source, means forope'rating-said circuitcloser to break the connection between said faster repeater andfsaidsource when the system is de-energized, andv means brought into actionwhen the system isfagain energized 'for imparting rotation to saidfaster motor prior to its connection-to Vsaid source, closing a circuitthriisaidfaster motor when the latter has attained a certainrelationship to the slower motor, and subsequently operating saidcircuit closer vto connect said faster motor with said source.

i 25. In 'a Synchronous transmission system, a plurality ofeiectr-icrepeater motors adapted to be driven at different speeds, acircuit closer -for connecting'the faster motor to a source 'ofelectrical supply, means for operating said circuit closer. todisconnect said motor from said source upon failure of current in thesystem, indicators driven by said motors, respectively, and meansbrought into action uponvthe establishment of current in the system forlirst imparting rotation to the faster motor, then closing a circuitthrough said faster motor when the inmeans brought into action uponexcitation dicators are in such relation that one supof the system forimparting rotation to said plements'the readings of the other,and thenmotor prior to closing n circuit there- 10 operating said circuit closerto connect the through. 5 faster motor to said source. In testimonywhereof I 'have athxed my 26. A synchronous transmission systemsignature. including? an electric repeater motor, and ELMER A. SPERRY,

